Gel catalysts and process for preparing thereof

ABSTRACT

A gel composition substantially contained within the pores of a solid material for use as a catalyst or as a catalyst support in dehydrogenation and dehydrocyclization processes.

This application claims the benefit of the filing date of U.S.Provisional Application No. 60/177,795, which was filed on Jan. 24, 2000(now pending); and U.S. Provisional Application No. 60/189,765, whichwas filed on Mar. 16, 2000, (now pending).

FIELD OF THE INVENTION

The present invention relates to a novel composition comprising a gelthat has utility as a catalyst or as a catalyst support. Also disclosedare methods of preparing the compositions and processes for using thecompositions for the dehydrogenation of C₂₋₁₀ hydrocarbons.

BACKGROUND OF THE INVENTION

The dehydrogenation of paraffins to olefins is commercially significantbecause of the need for olefins for the manufacture of high octanegasolines, elastomers, detergents, plastics, ion-exchange resins andpharmaceuticals. Important hydrocarbon dehydrocyclization reactionsinclude the conversion of diisobutylene and isooctane to p-xylene.

Processes for the conversion of paraffin hydrocarbons to less saturatedhydrocarbons are known. For examples, see U.S. Pat. No. 4,513,162, U.S.Pat. No. 5,378,350 and European Pat. Application EP 947,247 (published).Nonetheless, there is a continuing need to develop new compositions thatare more effective catalysts than those currently available indehydrogenation processes.

SUMMARY OF THE INVENTION

The present invention discloses a composition of matter, comprising: (i)a solid material having pores; (ii) a gel, said gel being substantiallycontained within the pores of said solid material and comprising atleast one catalytically active element, and optionally when saidcatalytically active element is other than Cr, comprising chromium inaddition to said element.

Another disclosure of the present invention is a process for preparing acomposition of matter comprising: a solid material having pores; a gel,said gel being substantially contained within the pores of said solidmaterial and comprising at least one catalytically active element, andoptionally when said catalytically active element is other than Cr,comprising Cr in addition to said element, said process comprising:contacting in the presence of a solid material having pores, in anyorder a protic solution with a non-aqueous solution wherein saidnon-aqueous solution comprises a gel-forming precursor and wherein oneof either the protic solution or the non-aqueous solution comprises atleast one soluble compound comprising an inorganic element selected fromthe group consisting of Group 1 through Group 16 and the lanthanides ofthe Periodic Table, under conditions such that the solution added firstis at incipient wetness, whereby gel formation occurs substantiallywithin the pores of said solid material.

A further disclosure of the present invention is a composition of matterprepared by the process described immediately above.

The present invention also discloses an improved gel composition,wherein said improvement comprises: said gel is substantially containedwithin the pores of a solid material.

Yet another disclosure of the present invention is a method of using thecomposition disclosed wherein said method comprises contacting in areactor said composition with a hydrocarbon feed in a dehydrogenation ordehydrocyclization process, said hydrocarbon being from C₂ to C₁₀.

DETAILED DESCRIPTION OF THE INVENTION

The solid material having pores is selected from the group consisting ofalumina, silica, titania, zirconia, carbon, molecular sieves (forexample, zeolites), porous minerals (such as bentonite), microporous,mesoporous and macroporous materials, montmorillonites, aluminosilicateclays (for example, bentonite), binary ternary, quaternary and higherorder oxides such as e.g., Fe₂O₃, NiO, CaO and CeO₂ (binary oxides),FeNbO₄, NiWO₄ and Sr₂TiO₄ (ternary oxides) and Ca₂MgSi₂O₇ (quaternaryoxide), carbides, nitrides, phosphates, and sulfides. These materialsare used as supports for the gels.

Higher order oxides are oxides beyond quaternary that contain more thanfour elements, including oxygen. Some examples of higher order oxidesinclude ganomalite (Pb₉Ca₅MnSi₉O₃₃), a lead calcium magnesium silicate,sodium calcium nickel arsenate (NaCa₂Ni₂As₃O₁₂) and barium coppereuropium lanthanum thorium oxide(Ba_(1.33)La_(0.67)Eu_(1.5)Th_(0.5)Cu₃O_(8.89)).

Catalytically active elements, which can be present as oxides, reducedmetals, and in some cases phosphates of Group 1 (Li, Na, K, Rb, Cs),Group 2 (Be, Mg, Ca, Sr and Ba), Group 3 (Y, La) and the lanthanides(Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm Yb and Lu) of the PeriodicTable can be used in C—H activation catalytic chemistries. Examplesinclude methane coupling reactions to produce ethane and ethylene. Incombination with other oxides of Groups 5, 6, 7, 8, 9, 10 of thePeriodic Table, Groups 1, 2, 3 and the lanthanides can also be used forother oxidation chemistries. Alkane and olefin oxidation are twoexamples. Group 5 (V, Nb, Ta), Group 6 (Cr, Mo, W), Group 7 (Mn, andRe), and Group 9 (Fe, Ru, Os), can be used for oxidation reactions ofalkanes and olefins. Two examples are the oxidation of butane to maleicanhydride and propylene oxidation to form acrolein. Elements of Group 10(Ni, Pd, Pt) and Group (11, Cu. Ag, and Au) can be used for alkane andolefin oxidation reactions, CO abatement, and for Pd, Pt, hydrogenationchemistries such as hydrogenation of ethylene to ethane. Ag and itsoxides can be used in epoxidation reactions, such as the epoxidation ofethylene to produce ethylene oxide. Elements of Group 15, especially P,As, Sb Bi can be used for oxidation reaction chemistries, such as theammoxidation of propylene to acrylonitrile, especially when combinedwith elements of Group 6 (Cr, Mo, and W) to form various oxidecombinations. Elements and their oxides of Group 16 (S, Se and Te) canbe used for dehydrosulfurization chemistries, which are used to treatsulfur containing streams from petroleum distillates.

The gel is prepared from at least one soluble compound comprising aninorganic element precursor wherein at least one element is selectedfrom the group consisting of Group 1 (i.e., Li, Na, K, Rb and Cs); Group2 (i.e., Be, Mg, Ca, Sr and Ba); Group 3 (i.e., Y and La); Group 4(i.e., Ti, Zr and Hf); Group 5 (i.e., V, Nb and Ta); Group 6 (i.e., Cr,Mo and W); Group 7, (i.e., Mn and Re); Group 8 (i.e., Fe, Ru and Os);Group 9 (i.e., Co, Rh and Ir); Group 10 (Ni, Pd and Pt); Group 11 (Cu,Ag and Au); Group 12 (i.e., Zn and Cd); Group 13 (i.e., B, Al and In);Group 14 (i.e.; Si, Ge, Sn and Pb); Group 15 (i.e.; P, As, Sb and Bi);Group 16 (i.e., S, Se and Te) and lanthanides (i.e.; Ce, Pr, Nd, Sm, Eu,Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu) of the Periodic Table.

In the present invention one or more inorganic alkoxides or saltsthereof is used as starting material, or precursors, for preparing thegels. The gel-forming precursor comprises at least one soluble compoundcomprising an inorganic element wherein the element is selected from thegroup consisting of aluminum, silicon, titanium zirconium, niobium,tantalum, vanadium, molybdenum and chromium. The alkoxides are thepreferred compounds, and metal alkoxides are most preferred.

The inorganic metal alkoxides used in this invention may include anyalkoxide which contains from 1 to 20 carbon atoms and preferably 1 to 5carbon atoms in the alkoxide group, which preferably are soluble in theliquid reaction medium. Examples include, but are not limited to,tantalum n-butoxide, titanium isopropoxide, aluminum isopropoxide andzirconium isopropoxide. These alkoxides are preferred.

Inorganic materials have a range of pore sizes. Pore dimensions for someinorganic materials are relatively small. The present inventiondiscloses gel-forming precursors that fit within the pore structure ofthe solid materials that are used. Commercially available alkoxides canbe used. However, inorganic alkoxides can be prepared by other routes.

Inorganic alkoxides can be prepared in various ways. One method ofpreparation includes direct reaction of zero valent metals with alcoholsin the presence of a catalyst. Many alkoxides can be formed by reactionof metal halides with alcohols. Also, alkoxy derivatives can besynthesized by the reaction of the alkoxide with alcohol in a ligandinterchange reaction. Direct reactions of metal dialkylamides withalcohol also form alkoxide derivatives. Additional methods for preparingalkoxides are disclosed in “Metal Alkoxides” by D. C. Bradley et al.,Academic Press, (1978).

The gel formed in the composition of the present invention is made bypreparing one or more non-aqueous alkoxide (or salt) solutions and aseparate solution of a protic solvent, such as water. Promoters andother reagents may be added to the solution(s) of alkoxides. When thealkoxide solution is mixed with the protic solvent the alkoxidehydrolyzes and cross-links to form a gel.

The solvent media used in the process generally should be a solvent forthe inorganic alkoxide or alkoxides which are utilized and theadditional metal reagents and promoters which are added in synthesis.Solubility of all components in their respective media (aqueous andnon-aqueous) is preferred to produce highly dispersed materials. Byusing soluble reagents in this manner, mixing and dispersion of theactive metals and promoter reagents can be near atomic, in factmirroring their dispersion in their respective solutions. The precursorgel thus produced by this process will contain highly dispersed activemetals and promoters. High dispersion results in catalyst metalparticles in the nanometer size range. These particles are substantiallycontained, or substantially localized, within the pores of the solidmaterial.

Typically, the concentration of the amount of solvent used is linked tothe alkoxide content. A molar ratio of 26.5:1 ethanol:total alkoxide canbe used, although the molar ratio of ethanol:total alkoxide can be fromabout 5:1 to 53:1, or even greater. If a large excess of alcohol isused, gelation will not generally occur immediately; some solventevaporation will be needed. At lower solvent concentrations, it isthought that a heavier gel will be formed having less pore volume andsurface area.

In the process of the present invention, the alkoxide solution withother reagents, water and additional aqueous solutions are contacted inthe presence of a solid having pores. Due to the surface area providedby the porous character of the solid material, hydrolysis andcondensation occurs substantially within the pores of the solid to formthe gel.

The amount of water utilized in the reaction is the amount calculated tohydrolyze the inorganic alkoxide in the mixture. A ratio lower than thatneeded to hydrolyze the alkoxide species will result in a partiallyhydrolyzed material which, in most cases, would reach a gel point at amuch slower rate, depending on the aging procedure and the presence ofatmospheric moisture. Generally, a molar ratio of water:alkoxide fromabout of 0.1:1 to 10:1 is used.

Reaction conditions and choice of gel-forming precursor (i.e., aprecursor which can react, hydrolyze and cross-link to form the gel)favors rapid hydrolyses and condensation reactions inside the pores ofthe solid material. These hydrolyses and condensation reactions need tobe more rapid than any reactions that occur outside the pores of thesolid material.

The molar ratio of the total water added to total catalytically activeelement added (for example, Ti, Zr, Ta, and Al), including water presentin aqueous solutions, varies according to the specific inorganicalkoxide used. For tantalum(alkoxide)₅ ratios close to 5:1 can be used.Also, a ratio of 4:1 can be used for zirconium(alkoxide)₄ andtitanium(alkoxides)₄. The addition of acidic or basic reagents to theinorganic alkoxide medium can have an effect on the kinetics of thehydrolysis and condensation reactions, and the microstructure of theoxyhydroxide matrices derived from the alkoxide precursor that comprisesthe soluble inorganic element. Generally, a pH within the range of from1 to 12 can be used, with a pH range of from 1 to 6 being preferred.

The first addition step is done under conditions of incipient wetness.The order of addition is not important, i.e., the either the proticsolvent or the non-aqueous solvent can be added initially. The secondaddition step can optionally be done under incipient wetness conditions.

After gel formation occurs within the pores of the solid material, itmay be necessary to complete the gelation process with some aging of thegel composition. This aging can range form one minute to several days.In general, the gel is aged in the pores of the solid material at roomtemperature in air for at least several hours.

Removal of solvent from the gel composition can be accomplished byseveral methods. Removal by vacuum drying or heating in air results inthe formation of a xerogel. A gel that is an aerogel of the materialtypically can be formed by charging in a pressurized system such as anautoclave. The gel composition can be placed in an autoclave where itcan be contacted with a fluid above its critical temperature andpressure by allowing supercritical fluid to flow through the gelmaterial until the solvent is no longer being extracted by thesupercritical fluid. In performing this extraction to produce an aerogelmaterial, various fluids can be utilized at their critical temperatureand pressure. For example, fluorochlorocarbons typified by Freon®fluorochloromethanes (e.g., Freon® 11 (CCl₃F), 12 (CCl₂F₂) or 114(CClF₂CClF₂), ammonia and carbon dioxide are all suitable for thisprocess. Typically, the extraction fluids are gases at atmosphericconditions. The pores collapse due to the capillary forces at theliquid/solid interface are avoided during drying.

The gels formed within the pores of the solid material, whether they arexerogels or aerogels, can be described as precursor salts dispersed inan oxide or oxyhydroxide matrix. The theoretical maximum for hydroxylcontent corresponds to the valence of central metal atom. Hence,Ta₂(O_(2−x)(OH)_(x))₅ possesses a theoretical hydroxyl maximum when x is2. The molar H₂O:alkoxide ratio can also impact the final xerogelstoichiometry; in this case, if H₂O:Ta is less than 5, there will beresidual —OR groups in the unaged gel. However, reaction withatmospheric moisture will convert these to the corresponding —OH, and —Ogroups upon continued polymerization and dehydration. Aging, even underinert conditions, can also effect the condensation of the —OH,eliminating H₂O, through continuation of crosslinking andpolymerization, i.e., gel formation.

The gel compositions of the present invention have utility as catalystsor as improved catalyst supports. The solid material having poresprovides mechanical integrity for the gel and generally does not inhibitthe catalytic properties of the gel. The mechanical integrity permitseasier handling and transportation of the gel compositions since,without the solid material, these compositions are fluffy andpowder-like, and not easily contained. In turn, the gel compositionsdisclosed herein reduce waste and therefore, is more cost efficient.

One particular use of the compositions of the present invention is inthe dehydrogenation of C₂ to C₁₀ hydrocarbons. In the dehydrogenationprocess disclosed herein, the hydrocarbon feed that can be used in thepresent invention includes any C₂ to C₁₀ hydrocarbon with ethane,propane, isobutane and isooctane (2,2,4-trimethylpentane) beingpreferred. The gel compositions contained within the pores of the solidmaterials disclosed in the present invention can be used as catalysts bycontacting the gel composition with the hydrocarbon feed in adehydrogenation process in a reactor. The contacting step may be done invarious types of reactors, including a fixed bed, moving bed, fluidizedbed, ebullating bed and entrained bed. The less saturated hydrocarbonreaction products of this invention can be separated by conventionalmeans such as distillation, membrane separation and absorption.

The gas hourly space velocity (GHSV) of the feed gas generally is in therange of from about 100 to about 3000 cc hydrocarbon feed/cc gelcomposition/hour, preferably from about 500 to about 1000 cc hydrocarbonfeed/cc gel composition/hour. The operating pressure is generally in therange of from about 7 kPa to about 700 kPa, preferably from about 7 kPato about 400 kPa. The dehydrogenation reaction temperature generally isin the range of from about 300° C. to about 650° C., preferably fromabout 450° C. to 600° C.

The gel-containing compositions of this invention can be regeneratedperiodically to remove coke. The regeneration is done by conventionaltechniques of carbon removal such as heating with an oxygen-containinggas, preferably air.

The compositions of the present invention are also useful as catalystsupports. For example, a chromium/aluminum gel supported in eta-alumina,prepared as described in Example 1 below, can be impregnated with awater soluble compound of platinum. One such example would beimpregnation with H₂PtCl₄. The impregnated support is then dried andheated to 400° C. in a 5% hydrogen/nitrogen stream for 4 hours and thencooled. The reduced supported catalyst is then suspended in a solventcontaining 1-hexene. The suspension is then heated at about 100° C. withstirring under a hydrogen atmosphere at about 3000 kPa for about twohours. Hexane can be separated from the reaction mixture.

In addition to the utility disclosed above, the compositions of thepresent invention also can be used as catalyst supports for oxidation(e.g., supported cobalt) and hydroformylation (e.g. supported rhodium)reactions.

The process for making the present invention may be implemented by usingcombinatorial methods for the rapid syntheses of catalysts. Such methodswould permit the production of these catalysts using robotic tools, suchas liquid delivery system, to a solid having pores, as described in thepresent invention, to create gel compositions substantially in the poresof the solid.

EXAMPLES

The catalyst charge was 2 mL for all the examples.

General Procedure for Catalyst Testing

Catalyst tests were performed in a fixed bed continuous flow quartzreactor with 6.4 mm id. The catalyst charge was 2.0 mL of −12/+20 mesh(−1.68/+0.84 mm) granules. The reactor tube was heated in a tube furnaceto 550° C. in flowing nitrogen until the temperature was stable. Athermocouple inside the catalyst bed was used to measure temperature.Once the desired temperature was achieved, a feed consisting of 50%isobutane/50% nitrogen (Examples 1 to 4) or a feed consisting of 50%propane/50% nitrogen (Examples 5 to 6) were passed over the catalystbed. The contact times 3.2 seconds in all the examples. The entireproduct stream was analyzed on-line using sampling valves and an HP 5890chromatogram (TCD)/HP 5971 mass selective detector.

The gel compositions prepared in the Examples below were used indehydrogenation processes. The results are tabulated and are shown belowin Table 1 (isobutane dehydrogenation) and Table 2 (propanedehydrogenation).

Legend C₃ is CH₃CH₂CH₃ iC4 is (CH₃)₂CHCH₃ Conv. is conversion Sel. isselectivity C₃═ is CH₂═CHCH₃ iC4═ is (CH₃)₂C═CH₂

Example 1 (Cr_(0.2)Al_(0.8))_(0.0383)(eta-Al₂O₃)_(0.96169)

A sol gel of chromium hydroxide acetate/aluminum isopropoxide containedin the pores of eta alumina was prepared as follows: eta alumina (8.0 g,N₂ BET surface area=401.9 m²/g, pore volume=0.327474 cc/g) was used. Anaqueous solution containing 0.1 M (with respect to chromium)(Cr₃(OH)₂)(ac)₇ was prepared by dissolving the chromium salt (4.022 g)in a sufficient quantity of commercially available ammonium hydroxidesolution (28-30% NH₄OH in water) to bring the solution volume to 200 mL.In a first sol gel preparation, the chromium solution (5 mL) was firstadded dropwise to the eta alumina support with agitation. Followingaddition of the aqueous solution, 0.05 M aluminum isopropoxide inisopropanol (20 mL) was slowly added to the wet support. Excess solventwas used in this preparation (however, the aluminum isopropoxide willdeposit inside of the pores of the supports to graft onto it). The solidwas allowed to dry in air prior to the second impregnation.

In a second cycle, additional chromium solution (2.5 mL) was added, andadditional aluminum isopropoxide solution (20 mL) was added into thesupport. In a third cycle, 2.7 mL of the chromium solution was used, and20 mL of the aluminum isopropoxide solution was employed. In a fourthcycle, 2.2 mL of the chromium solution was added along with 0.3 mL ofNH₄OH solution was added, followed by 20 mL of the aluminum isopropoxidesolution. The final cycle involved the addition of 2.5 mL of ammoniumhydroxide solution (only) followed by 20 mL of the aluminumisopropoxide. The final material was dried under vacuum for 5 hours at120° C. The material was pelletized and granulated and sieved on −10,+20 mesh (−2.0, +0.84 mm) screens prior to reactor evaluations. Highresolution transmission electron microscopy depicted Example 1 andshowed that the chromium-alumina gel is essentially within the pores ofthe eta-alumina solid material (support).

Example 2 Cr_(0.0182)Al_(0.0285)(TiO₂)_(0.9533)

A portion (7.7 mL) of the 0.1 M (with respect to chromium)solution ofchromium hydroxide acetate described in Example 1 was added to titaniumoxide (8 g), followed by 20 mL of the 0.05 M aluminum isopropoxidesolution (described in Example 1) to add the alkoxide into the support.In a second cycle, 6.7 mL and 20 mL of the chromium and aluminumsolutions, respectively, were used. In a third cycle, 4.75 mL and 20 mLof the chromium and aluminum solutions, respectively, were used. Thefinal material was dried under vacuum for 5 hours at 120° C. Thematerial was pelletized and granulated and sieved on −10, +20 mesh(−2.0, +0.84 mm) screens prior to reactor evaluations.

Example 3 5.261 wt % (CrO_(1.5)), 1.193 wt % (AlO_(1.5)), 93.546 wt %Bentonite Clay

Bentonite clay (8 g) was used as a support. A 2.5 mL portion of the 0.1M (with respect to chromium) chromium hydroxide acetate solution fromExample 1 was used, followed by 20 mL of the aluminum isopropoxidesolution from Example 1. One additional cycle was used to bring thecatalyst to the final loading. The final material was dried under vacuumfor 5 hours at 120° C. The material was pelletized and granulated andsieved on −10, +20 mesh (−2.0, +0.84 mm) screens prior to reactorevaluations.

Example 4 Cr_(0.003432)Al_(0.0137266)/C_(0.9828414)

A 5 mL portion of the 0.1 M (with respect to chromium) chromiumhydroxide acetate solution from Example 1 was added to carbon black(6.88 g) followed by 40 mL of the aluminum isopropoxide solution. In asecond cycle, 5 mL of the chromium solution and 40 mL of the aluminumhydroxide solution were used. A third cycle used 5 and 40 mL, and afourth cycle 4 and 40 mL were used. The final material was dried undervacuum for 5 hours at 120° C. The material was pelletized and granulatedand sieved on −10, +20 mesh (−2.0, +0.84 mm) screens prior to reactorevaluations.

Example 5 CrO_(0.0182)Al_(0.0285)(TiO₂)_(0.9533)

This example was prepared as described in Example 2.

Example 6 5.261 wt % (CrO_(1.5)), 1.193 wt % (AlO_(1.5)), 93.546 wt %Bentonite Clay

This example was prepared as described in Example 3.

Example 7 Cr_(0.003432)Al_(0.0137266)/C_(0.9828414)

10 grams of a sample from Example 4 was suspended in 10 mL of watercontaining 1 gm of K₂PtCl₄. The sample was heated to 400° C. in a 5%hydrogen/nitrogen stream for 4 hours and cooled. The reduced catalyst(0.100 g) was suspended in 1 mL of hexane containing 0.200 gm of1-hexene and heated to 100° C. with 500 psig H₂ for 2 hours. GC analysisof the product showed greater than 95% selectivity for hexane.

TABLE 1 ISOBUTANE DEHYDROGENATION Ex. % iC₄ % iC₄═ % CH₄ % C₂-C₄ %Others No. Conv. Sel. Sel. Sel. Sel. 1 37.2 27.4 31.4 38.4 2.3 2 32.160.9 24.4 14.8 0 3 6.9 64.4 0 35.6 0 4 12.4 83.4 0 16.6

TABLE 2 PROPANE DEHYDROGENATION Ex. % C₃ % C₃═ % C₂ % Others No. Conv.Sel. Sel. Sel. 5 23.0 86.4 8.2 5.5 6 3.2 55.8 40.0 4.2

What is claimed is:
 1. A composition of matter comprising (a) a solidmaterial having pores, and (b) a gel; wherein the gel is substantiallylocalized within the pores of the solid material; and wherein the gelcomprises at least one catalytically active element, and optionallycomprises chromium when the catalytically active element is other thanchromium.
 2. The composition of claim 1 wherein the solid materialhaving pores is selected from the group consisting of alumina, silica,titania, zirconia, carbon, molecular sieves, porous minerals,microporous, mesoporous and macroporous materials, montmorillonites,aluminosilicate clays, and binary, ternary, quaternary and higher orderoxides, carbides, nitrides, phosphates, and sulfides.
 3. The compositionof claim 2 wherein said catalytically active metal is selected from thegroup consisting of platinum and gold.
 4. The composition of claim 1wherein said catalytically active element is chromium and said solidmaterial having pores is alumina.
 5. A gel composition comprising a gelthat is substantially localized within the pores of a solid materialselected from the group consisting of alumina, silica, titania,zirconia, carbon, molecular sieves, porous minerals, montmorilloniteclay, alumninosilicate clays, carbides, nitrides, phosphates, andsulfides.
 6. A process for preparing a composition of matter comprising(a) a solid material having pores, and (b) a gel; wherein the gel issubstantially contained within the pores of the solid material; whereinthe gel comprises at least one catalytically active element, andoptionally comprises chromium when the catalytically active element isother than chromium; wherein the process comprises contacting a solidmaterial having pores with, in any order, a protic solution and anon-aqueous solution; wherein the solution added first is at incipientwetness; wherein one of either the protic solution or the non-aqueoussolution comprises at least one soluble compound comprising an inorganicelement selected from the group consisting of Li, Na, K, Rb, Cs, Be, Mg,Ca, Sr, Ba, Y, La, Ti, Zr Hf, V, Nb, Ta, Cr, Mo, W, Mn, Re, Fe, Ru, Os,Co, Rh Ir, Ni, Pd Pt, Cu, Ag, Au, Zn, Cd, B, Al, In, Si, Ge, Sn, Pb, P,As, Sb, Bi, S, Se Te, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb andLu and lanthanides of the Periodic Table; wherein the non-aqueoussolution comprises a gel-forming precursor; and wherein gel formationoccurs substantially within the pores of the solid material.
 7. Theprocess of claim 6 wherein the solid material laving pores is a catalystsupport selected from the group consisting of alumina, silica, titania,zirconia, carbon, molecular sieve, porous mineral, montmorillonite clay,aluminosilicate clay, carbide, nitride, phosphate, and sulfide; and saidgel-forming precursor comprises at least one soluble compound comprisingan inorganic element selected from the group consisting of aluminum,silicon, titanium, zirconium, niobium, tantalum, vanadium, molybdenumand chromium.
 8. The process of claim 7 wherein the catalyst support isalumina, and the gel-forming precursor is a chromium salt.